I Know What You'll Do
by ToucheDetective
Summary: 'The soft leather cuff tightens around her wrist, the first of her limbs to be thoroughly secured and her heart rate spikes as she tries to remember how in the hell she agreed to this.' Post ep for 1x06 Always Buy Retail. One-shot.


_Owe you what_

The soft leather cuff tightens around her wrist, the first of her limbs to be thoroughly secured and her heart rate spikes as she tries to remember how in the _hell_ she agreed to this.

When she woke up this morning, getting shot at was probable. Having Castle save her life, however unlikely, could still happen. But nowhere in the realm of extreme possibility was allowing Castle to cuff her to her own bed and do with her as he pleased.

Champagne glass in hand, he had stalked towards her saying she owed him, innuendo so thick she was sure it was a joke. But he leaned in close, goose bumps chasing down her neck when he breathed in her ear and asked to perform a thorough investigation of his own.

On her.

He didn't say what exactly he was going to do and she didn't ask.

Stunned but thoroughly turned on, she'd agreed to it. She told herself she was just calling his bluff, proving that he was all talk and no action, dismissing the thrill that zipped through her blood at his suggestion as just leftover adrenaline from the takedown.

But he had been insufferable after the shootout. Cocky. Whispering in her ear all the questions he'd have answers to tonight like ' _What makes you beg, Beckett?_ ' and ' _I wonder what you taste like._ '. Clearly formulating his plan of attack, he'd undressed her with his eyes while she tried valiantly to focus on paperwork but her flushed skin betrayed her, anticipation all consuming until she'd almost bitten her lip raw.

Trying to figure out exactly what he was planning only made it worse, images of this 'investigation' of his had her mind filled with their naked bodies, those wandering talented hands, and sounds that are not appropriate for the work place.

And here she is, wet and wanting and willingly not in control of anything, practically daring him to prove he is as good as he says. She tries her best to not look affected, but the flutter of her eyelids gives her away, the hiss through her teeth revealing just how much she wants this. _Oh God, yes does she want this._

He has her on her back, cuffed to her bed, backwards of course, feet against the headboard and hands at the bottom because this is Castle after all and when does he ever do anything like a normal person.

She should be freaking out right now, but for some inexplicable reason she _trusts_ him.

He pulls out the fourth strap from under the mattress and she doesn't even think to ask how he knew they were there, distracted by the flex of his biceps straining against rolled up sleeves. The crisp clean scent of his aftershave invades her senses as he secures the last of her limbs, spreading one leg from the other, parts of her body in between naturally following suit and making her breath hitch.

She's completely at his mercy now, exposed even with her robe on and securely tied, the slippery black silk shifting with each breath, thin fabric draped precariously between him and all the evidence he'll ever need to prove how much she wants him.

His fingers skate up one thigh, up, up, disappearing under the hem of her robe and she inhales sharply as the cuffs keep her legs apart, preventing them from clamping together – to keep him in not out, even though she'd never admit it.

But he stops moving his hand.

"Oh, no, that would be too easy. The buildup is half the fun. I'm going to drag this out until you can't take it anymore." He punctuates his words by dragging the tie of her robe against the barely covered apex of her thighs, his mouth brushing hers.

"I want you dripping." He claims the whimper that escapes her parted lips, stealing her breath right out of her lungs until she's dizzy with want, her body already flooding at his words.

 _Anything I want_

Predatory. That's the only way to describe it as he strolls around to the foot of the bed, the growing bulge in his pants just inches from her head, making her mouth water when he leans over her to run his fingers up the inside of her arm, a barely there touch that makes her involuntarily struggle against her shackles, a sharp reminder that she can't do a damn thing about it.

Arousal sizzles low in her belly as his gaze rakes over her body, blue eyes piercing the darkness of her room, deciding where to start first and her mind fills with all the filthy things he could do, all the things he could get away with in the privacy of her apartment.

He pauses, gives her a second, let's her wonder what's coming before roughly kneading her flesh wherever he pleases.

His touch is bold, possessive, making her gasp and squirm against the restraints that keep her in place as he massages her breasts, flicking his thumbs over her nipples through the silk, the deluge of heat to her core making her feverish. The hem of her short robe inches higher with the roam of his hands over her chest, threatening to slip open, her twitches and trembles doing nothing to help it stay.

He eases back to a sweeping, feather-light touch that wanders over her chest, skates his nails over her breasts, culminating in small circles until he's barely touching her nipples.

It's _not enough_.

She tries and fails to press up into his hands, the painstakingly light strokes driving her mad, holding her away from the edge.

He suddenly pinches the over sensitized peaks, her deep, throaty moan accompanying a shudder and she struggles to keep her eyes open, her full attention on his roaming fingertips as she tries to anticipate where he's headed next.

She knows all she has to do is say what she wants, beg, but this is _Castle_ and he doesn't need his ego stroked. She can think of better things to stroke. Maybe make _him_ beg. But he's the one in absolute control, teasing her into a quivering mess of pure need, waiting to be filled by him.

The edges of the robe tickle her chest when his fingers slip underneath and he takes his time dragging the material to the side, caressing her stomach and ribs with it, exposing her skin to the cool night air and causing her nipples to pebble even further.

Her chest heaves as he studies her newly revealed skin from the belly button up, his eyes turning blacker by the second and she can only bite her lip and watch.

He pounces then, her body a maelstrom of pleasure, his touch everywhere at once, nibbling, licking, tasting. She wants to touch, grab, wrap her arms and legs around him and gain some sort of control or participate or _some_ thing but _she can't_.

All she can do is lie there and take it, forced to fully focus on the wicked bombardment of sensation his hands and teeth and tongue invoke. Every touch is electrifying, the perfect storm of pleasure. If she'd known he was this good maybe she would have given that 'debrief' he had suggested after their first case a little more consideration because _damn_.

Unintelligible whispers spill from his lips and caress her skin, her mind hazy with lust, the sound of her pulse rushing in her ears and she's almost ready to fly apart despite him never touching her where she needs it most and then he abruptly _stops_.

"Not yet, Detective," he drawls and _oh_ she's going to _kill_ him.

She's just about to tell him that when he kisses her, the play of his lips and tongue gentle, hypnotic, and intoxicating. When she's thoroughly drugged by the play of his mouth, he pulls back slightly, nipping her lip. "This time I want to hear you," he practically growls against her, sending a shiver down her spine at the dark tone.

He climbs on the bed, kneeling in between her knees and unbuckling his belt and _oh god_ _yes_ but he only unzips his pants to relieve the pressure before leaning over her and running his hands up the length of her legs.

He meanders up the inside of one and down the other, skipping her center completely and she whimpers, her body tingling up the path he was supposed to take, the path she desperately _wants_ him to take. He's being exasperatingly torturous on purpose, the bastard.

She _hates_ him.

She needs him to _fucking touch her_ before she spontaneously combusts.

Sharp, shallow pants replace her breathing when he finally undoes her sash, eases the robe fully open, fanning it out at her sides and leaving her completely bare to him. His thumbs dance in the dip between her thigh and abdomen and her hips jolt in the cradle of his hands, anticipation driving her insane and _fuck_ , Castle, come _on_.

His face hovers in closer to the vee of her legs, licking his lips at what he sees there. She lets out a mewl of encouragement but he veers to the side at the last possible second, attaching his mouth to the jutting bone of her hip.

She lets out a strangled cry at the grip of his teeth, the cuffs jerking her movements to a halt, only allowing her hips to thrust up further into him, her inner muscles clenching at nothing, denying her the satisfaction she desperately needs and she curses him under her breath.

 _And you know exactly what I want_

"I want you to say it, Beckett."

"Castle-" She wines, writhes, chases his mouth and fingers with her hips as best she can.

"Say it."

" _Please_." She's too far gone to even realize she's begging, ready to say anything he wants if it means he'll get her off.

"Please what?" His grin is infuriating. "Use your words."

She groans when he repeats the path from earlier, fingers brushing even higher, barely grazing her center, making her throb unbearably between her legs and god damn it, Castle. She needs it hard and fast and _now_.

" _Fuck me._ "

She wakes up at her own words, sliding one finger through her drenched folds and slipping straight into her core. One finger that she imagines is his and she's falling, panting into her pillow and gripping the impostor digit as he calls to her from her dream, his voice floating through her head, ' _That's it, Kate'_.

It's quick and it's dirty and she hates herself for it.

She rolls onto her back and runs her other hand through her hair, wondering what the hell is wrong with her, hating that he got to her, that she wants that self-centered egotistical jackass of a playboy. God _damn it_ does she want him.

' _Never, ever call me kitten.'_ Seriously?! Of all the things he could have asked for. It goes against his playboy persona, and maybe that's what it is, just a persona and no no no that only makes him more appealing.

He was a complete gentleman after that innocent tease in the hallway. Her mind, however, was entrenched in the gutter, waiting (hoping?) for him to needle her with personal questions or ask for a date or favors of an illicit nature. The ideas her traitorous mind came up with were downright pornographic, her body equally traitorous in its enthusiastic response.

Just thinking about it brings her need back up to a ten, the relief from seconds ago brief and unsatisfying. She reaches for her nightstand and the vibrator that lies within but she hesitates, toying with the knob as indecision wracks her still hazy mind.

She knows it will be about Castle. All she can think about is him. Castle and his stupid smug grin like somehow he knows exactly how much he's affected her. Like he _knows_ exactly what she's about to do.

She pulls open the drawer.

Fuck it.

* * *

 _A/N: The title is part of a lyric from "Once Upon a Dream". Shout out to my partner in crime who loves to help with 'research' and also to howthisworks-caskett for being my first ever beta. Thanks for reading!_


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